Conventionally, there is known a substrate conveying device which takes (carries) substrates such as glass substrates out of a cassette (see e.g. Patent Literature 1).
This substrate conveying device includes conveying rollers arranged in two rows, and a hand unit. The conveying rollers in the rows are arranged such that they are apart from each other in a direction in which the substrates are conveyed. The hand unit extends in a direction perpendicular to the direction in which the substrates are conveyed, and is positioned to be slightly lower than the conveying rollers. The hand unit has on its upper surface plural ejection holes through which compressed air supplied from a blower or the like is ejected. When the substrates are taken out of the substrate cassette, the both end portions of the lower surface of each of the substrates are directly supported by the conveying rollers, a portion of the substrate which portion is closer to the center than portions thereof which contact the conveying rollers is supported in a non-contact state by the compressed air ejected through the ejections holes, and the conveying rollers are rotated. In this configuration, each of the substrates is taken out of the substrate cassette due to a friction force generated by the contact with the conveying rollers.